Vehicles with four wheel independent suspensions generally require the adjustment of rear toe angles during the wheel alignment process. This adjustment typically involves manually lengthening or shortening a toe-link bar with a wrench to effect sufficient inward or outward toe movement to bring the toe angles within a specified error window.
Also well known in the art are steering systems which position the rear wheels of a vehicle in relation to the front wheel steering angle, sometimes in combination with the vehicle speed. In most systems, a single actuator or mechanical input positions both rear wheels via a steering rack or similar mechanism. Independent positioning of the rear wheels is also known.